Historically, taking inventory of saleable articles in a retail store has been a labor intensive process, which typically involves store personnel making rounds through the store and manually counting and logging quantities of each type of article. More recently, barcode scanning systems have been employed to increase the efficiency and accuracy of taking inventory. Using a barcode scanning system, articles within a store are tagged with barcodes, which are optically readable by handheld barcode scanners. In order to take inventory using such a system, store personnel still are required to make rounds through the store and scan each barcode with a barcode scanner. However, the barcode scanner is configured to log the barcode information electronically, thus reducing the time to log each article, and accordingly, reducing the overall time to take inventory. In addition, the barcode scanner reads and logs the barcode information more accurately than human personnel, which provides the benefit of increased accuracy of the inventory-taking process. However, due to the labor intensive nature of the inventory taking process with barcode scanners, a typical retail store may take a full inventory only once a year or so.
More recently, radio frequency identification (RFID) technologies have been exploited to increase the efficiency and potentially the accuracy of inventory-taking processes. Using this technology, an RFID tag is applied to each article for which inventory tracking is desired. The RFID tags are capable of transmitting an information-bearing, radio frequency signal (e.g., a signal that includes an identification number) in response to a tag interrogation signal from an RFID tag reader. In order to take inventory, store personnel with handheld RFID tag readers make rounds through the store and, at various locations, cause the RFID tag reader to interrogate any RFID tags that may be within range of the RFID tag reader. The information collected by the RFID tag reader may then be analyzed to generate an estimate of the current inventory. As with the barcode scanning system, an RFID system has the benefit of increased accuracy over manual inventory-taking processes. In addition, an inventory-taking process may be more efficiently performed using an RFID system, when compared with a barcode scanning system, since the individual who is taking inventory is not required physically to handle each tag in order to receive its identification information, and the RFID tag reader is able to receive responses from multiple RFID tags for each RFID tag interrogation signal that it transmits.
Although the use of barcode scanning systems and RFID systems have increased the efficiency and accuracy associated with taking inventory, the process still takes dedicated human resources and a significant amount of time to complete. Accordingly, even with RFID systems, a retail store may take inventory relatively infrequently (e.g., perhaps once a month, once a week, or less often). This lack of timely knowledge of the current inventory at a retail store may result in lost sales. In addition, neither system enables store personnel readily to determine the locations of particular articles within the store. Inaccurate knowledge of current inventory may, in some circumstances, lead to less-than-optimal customer satisfaction due to unavailability of desired articles or sizes and/or the inability to locate desired articles, for example. Accordingly, what are needed are inventory monitoring systems that enable inventory to be taken accurately and more often than is practicable with conventional, barcode scanner-based inventory systems. Further needed are inventory monitoring systems that enable specific articles readily to be located within a store or other controlled area.